Nickel-free vs conventional braces for patients allergic to nickel: Gingival and blood parameters during and after treatment.

Am J Orthod Dentofacial Orthop. 2016 Dec;150(6):1014-1019. doi: 10.1016/j.ajodo.2016.05.009.

Pazzini CA1, Pereira LJ2, Marques LS3, Ramos-Jorge J3, Aparecida da Silva T4, Paiva SM5.

1Postgraduate student, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: camilapazzini@hotmail.com.
2Professor, Department of Health Sciences, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil.
3Professor, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil.
4Professor, Department of Oral Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
5Professor, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.

Abstract

INTRODUCTION:

Allergic and inflammatory reactions have commonly been associated with the release of metal ions during orthodontic treatment. Our objective was to evaluate prospectively gingival and blood status in patients allergic to nickel.

METHODS:

Allergy to nickel was diagnosed using a patch test. Two groups were established: conventional braces (n = 21) and nickel-free braces (n = 21). The gingival index was used to determine gingival status before treatment, periodically for 12 months (evaluations every 3 months), and 1 month after the removal of the braces. Blood status was evaluated with a complete blood count, including the quantification of nickel and immunoglobin E before treatment, during treatment, and 1 month after removal of the braces. The data were analyzed using Mann-Whitney, Student t, Wilcoxon, repeated measures analysis of variance, Friedman, and chi-square tests. Either the Pearson or the Spearman correlation coefficients were calculated, when appropriate.

RESULTS:

The number of basophils increased significantly among the evaluations in both groups (conventional, P = 0.002; nickel-free, P = 0.001), whereas the number of eosinophils and the immunoglobin E levels decreased significantly in the conventional group (P = 0.004). Plasma nickel levels were increased before and during treatment, and decreased 1 month after removing the braces in both groups, but the differences were significant only in the nickel-free group (P = 0.002). No correlations were found between the concentrations of nickel and immunoglobin E, basophils, or eosinophils, or between the gingival index and either bands or segmented neutrophils (P ≥ 0.05).

CONCLUSIONS:

Patients treated with nickel-free braces had better gingival health and smaller blood changes than did those treated with conventional braces. All abnormalities tended to be eliminated after the removal of the braces.

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